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(No Model.)

0. A. STERLING.

CONNECTING ROD FOR RO GK DRILLS.-

No. 287,188. Patented Oct. 23, 1883:

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R fi I NITED STATES CONNECTING-ROD FOR RO'CK-DRILLS.

SPECIFICATION formingpart of Letters Patent No. 287,188, dated bctober23, 1883. I

Application filed February 21, 1882. (No model.) 7

To all whom it may concern:

Be it known'that I, CHARLES A. STERLING, a citizen of the United States,residing at New York, in the State of New York, have invented a new anduseful Connecti-ngRod for Rock-Drill Tools, of which the following is aSpecification.

' connecting-rod for lengthening the tool. Fig.

IV is a horizontal section of a coupling between piston-rod andcutting-tool.

Similar letters represent similar parts in all the figures.

Rock-drills have generally a motion on their supporting-frames of aboutthree feet, to move downward that distance as the cutting-toolpenetrates the rock. WVhen the cutting-tool has cut to this depth andthe hole is required a greater depth, the tool must be removed andlengthened or replaced by another tool about three feet longer.Experience has proved that the new cutting-tool must be made smalleracross the cutting-surface than the tool which has been replaced, and inmany cases the rockdrill has to be moved to get the old tool away andsubstitute therefor a new tool. The insertion of new tools of variouslengths, and, as above stated, of smaller diameter on theircutting-surface than the previous tool, produces an uneven hole, whilein many cases a good tempered tool could penetrate from twelve toeighteen, and more, feet, if the feeding motion of the rock-drill wouldallow it. All these inconveniences are considerably increased insubmarine drilling from above the surface of the water, and the deeperthe hole has to be drilled.

To obviate the necessity of removing the cutting-tool after the same hasdrilled the depth allowed by the construction of the rockdrill, and thenecessity of lengthening or replacing the same by a new and longercuttingtool, I arrange a connecting-rod, D, having at each end recessescorresponding with the recess made in the end of the piston-rod R of therock-drill A to receive the end of the cuttingtool B, (see Fig. 1,) aswell as corresponding couplings, 0, similar in construction to thecoupling 0, arranged at the end of the piston-- rod 1?. Into one end ofthis connecting-rod D the upper end of the cutting-tool B is fastened,

Figs. II and III, in the same manner as the same had previously beenfastened to the end of the piston-rod P, Fig. I. Into the other end ofsaid connecting-rod D a rod, R or R, is inserted and fastened, of such alength as to make the whole cutting-tool, consisting of the cutting-toolB, connectingrod D, and rod R or R, the required length to continue theoperation of drilling to the required depth.

The coupling-clutches which I adopt at the ends of the rod D and the endof the pistonrod P, although any other description of couplings may beused, are shown in section in Figs. I and IV, and consist of two clamps,aa, placed around-the end of the rods and fastened together by thehead-bolt b. These clamps are provided with projections on one of theirfaces, and with a corresponding recess upon the face of the oppositeclamp, which snugly fit into each other, to prevent twisting, lateral,or independent motion, whereby the drill-shaft is kept true and in aperpendicular position, and also serve to steady and strengthen the rodwhen subjected to great strain, one of, these clamps,a, acting against aplug, (Z, passing through the side of the rod and acting against the endof the cutting-tool B, or the ends of the rods R or R, inserted into theends of the piston-rod P or the connectingrod D.

WVhat I claim as my invention, and desire to secure by Letters Patent,is

l. The combination,with the piston-rod and shaft of a rock-drill, of aclamp consisting of the clamp-boxes a a, joined'as described, thekey-plug (2, arranged as set forth, and the U- shaped head-bolt 1),whereby the same are securely clamped and held together, substan tiallyas described.

2 The combination, with the drill-shaft of a rock-drill, of theclamp-boxes a a, fitted and joined as described, the U-shaped head-boltb, and key-plug d, the latter being recessed both into the drill-shaftand clamp, for the purpose set forth.

CHAS. A. STERLING.

\Vitnesses:

HENRY E. ROEDER, WM. H. CORNELL.

